:Iron(II) bromide

{{chembox

| Verifiedfields = changed

| verifiedrevid = 432513551

| Name = Iron(II) bromide

| ImageFile1 = FeBr2(aq)4.svg

| ImageFile2 = Cadmium-iodide-3D-layers.png

| ImageName = Iron(II) bromide

| IUPACName = Iron(II) bromide

| OtherNames = Ferrous bromide

| SystematicName =

| Section1 = {{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 74218

| InChI = 1/2BrH.Fe/h2*1H;/q;;+2/p-2

| InChIKey = GYCHYNMREWYSKH-NUQVWONBAN

| SMILES = [Fe+2].[Br-].[Br-]

| SMILES_Comment = anhydrous

| SMILES1 = Br[Fe-4](Br)([OH2+])([OH2+])([OH2+])[OH2+]

| SMILES1_Comment = tetrahydrate

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/2BrH.Fe/h2*1H;/q;;+2/p-2

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = GYCHYNMREWYSKH-UHFFFAOYSA-L

| CASNo_Ref = {{cascite|correct|??}}

| CASNo1 = 20049-61-0

| CASNo1_Comment= tetrahydrate

| CASNo2 = 7789-46-0

| CASNo2_Comment= anhydrous

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = EA3X054RBZ

| PubChem = 425646

| RTECS =

}}

| Section2 = {{Chembox Properties

| Formula = FeBr2

| MolarMass = 215.65 g mol−1

| Appearance = yellow-brown solid

| Density = 4.63 g cm−3, solid

| Solubility = 117 g / 100 ml

| Solvent = other solvents

| SolubleOther = THF, methanol, ethanol

| MeltingPtC = 684

| MeltingPt_notes = (anhydrous)
27 °C (Hexahydrate)

| BoilingPtC = 934

| MagSus = +13,600·10−6 cm3/mol

}}

| Section3 = {{Chembox Structure

| Coordination = octahedral

| CrystalStruct = Rhombohedral, hP3, SpaceGroup = P-3m1, No. 164

| Dipole =

}}

| Section4 =

| Section5 =

| Section6 =

| Section7 = {{Chembox Hazards

| ExternalSDS =

| MainHazards = none

| FlashPt =

}}

| Section8 = {{Chembox Related

| OtherAnions = Iron(II) fluoride
Iron(II) chloride
Iron(II) iodide

| OtherCations = Manganese(II) bromide
Cobalt(II) bromide

| OtherFunction_label = compounds

| OtherFunction = Vanadium(II) bromide
Iron(III) bromide

}}

}}

File:Бромид железа.jpg

Iron(II) bromide refers to inorganic compounds with the chemical formula FeBr2(H2O)x. The anhydrous compound (x = 0) is a yellow or brownish-colored paramagnetic solid. The tetrahydrate is also known, all being pale colored solids. They are common precursor to other iron compounds.

Structure

Like most metal halides, FeBr2 adopts a polymeric structure consisting of isolated metal centers cross-linked with halides. It crystallizes with the CdI2 structure, featuring close-packed layers of bromide ions, between which are located Fe(II) ions in octahedral holes.{{cite journal|doi=10.1524/ncrs.2001.216.14.544|title=Refinement of the crystal structure of iron dibromide, FeBr2|journal=Zeitschrift für Kristallographie - New Crystal Structures|volume=216|issue=1–4|year=2001|last1=Haberecht|first1=J.|last2=Borrmann|first2=Η.|last3=Kniep|first3=R.|doi-access=free}} The packing of the halides is slightly different from that for FeCl2, which adopts the CdCl2 motif. The tetrahydrates FeX2(H2O)4 (X = Cl, Br) have similar structures, with octahedral metal centers and mutually trans halides.{{cite journal |doi=10.1016/S0020-1693(00)80756-2| title=X-ray Structural Studies of FeBr2·4H2O, CoBr2·4H2O, NiCl2·4H2O and CuBr2·4H2O. Cis/Trans Selectivity in Transition Metal(II) Dihalide Tetrahydrate | year=1992 | last1=Waizumi | first1=Kenji | last2=Masuda | first2=Hideki | last3=Ohtaki | first3=Hitoshi | journal=Inorganica Chimica Acta | volume=192 | issue=2 | pages=173–181 }}

Synthesis and reactions

FeBr2 is synthesized using a methanol solution of concentrated hydrobromic acid and iron powder. It adds the methanol solvate [Fe(MeOH)6]Br2 together with hydrogen gas. Heating the methanol complex in a vacuum gives pure FeBr2.{{cite book|doi=10.1002/9780470132456.ch20|chapter=Iron(II) Halides|pages=99–104|year=1973|volume=14| last1=Winter|first1=G.|title=Inorganic Syntheses|isbn=9780470132456}}

FeBr2 reacts with two equivalents of tetraethylammonium bromide to give [(C2H5)4N]2FeBr4.N. S. Gill, F.. B. Taylor Inorganic Syntheses 1967, volume 9, page 136-142. {{doi| 10.1002/9780470132401.ch37}} FeBr2 reacts with bromide and bromine to form the intensely colored, mixed-valence species [FeBr3Br9].Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}

Magnetism

FeBr2 possesses a strong metamagnetism at 4.2 K and has long been studied as a prototypical metamagnetic compound.{{cite journal |last1=Wilkinson |first1=M. K. |last2=Cable |first2=J. W. |last3=Wollan |first3=E. O. |last4=Koehler |first4=W. C. |title=Neutron Diffraction Investigations of the Magnetic Ordering in FeBr2, CoBr2, FeCl2, and CoCl2 |journal=Physical Review |date=15 January 1959 |volume=113 |issue=2 |pages=497–507 |doi=10.1103/PhysRev.113.497|bibcode=1959PhRv..113..497W }}{{cite journal |last1=Jacobs |first1=I. S. |last2=Lawrence |first2=P. E. |title=Metamagnetic Phase Transitions and Hysteresis in FeCl2 |journal=Physical Review |date=10 December 1967 |volume=164 |issue=2 |pages=866–878 |doi=10.1103/PhysRev.164.866|bibcode=1967PhRv..164..866J }}

References